<?php
namespace TYPO3\CMS\Core\Collection;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

/**
 * Interface for collection class being persistable
 *
 * Collections are containers-classes handling the storage
 * of data values (f.e. strings, records, relations) in a
 * common and generic way, while the class manages the storage
 * in an appropriate way itself
 *
 * @author Steffen Ritter <typo3steffen-ritter.net>
 */
interface PersistableCollectionInterface {

	/**
	 * Get the identifier of the collection
	 *
	 * For database stored collections, this will be a integer,
	 * session stored, registry stored or other collections might
	 * use a string as well
	 *
	 * @return int|string
	 */
	public function getIdentifier();

	/**
	 * Sets the identifier of the collection
	 *
	 * @param int|string $id
	 * @return void
	 */
	public function setIdentifier($id);

	/**
	 * Loads the collections with the given id from persistence
	 *
	 * For memory reasons, per default only f.e. title, database-table,
	 * identifier (what ever static data is defined) is loaded.
	 * Entries can be load on first access.
	 *
	 * @param int|string $id
	 * @param bool $fillItems Populates the entries directly on load, might be bad for memory on large collections
	 * @return \TYPO3\CMS\Core\Collection\CollectionInterface
	 */
	static public function load($id, $fillItems = FALSE);

	/**
	 * Persists current collection state to underlying storage
	 *
	 * @return void
	 */
	public function persist();

	/**
	 * Populates the content-entries of the storage
	 *
	 * Queries the underlying storage for entries of the collection
	 * and adds them to the collection data.
	 *
	 * If the content entries of the storage had not been loaded on creation
	 * ($fillItems = false) this function is to be used for loading the contents
	 * afterwards.
	 *
	 * @return void
	 */
	public function loadContents();

}
